Sam Laidlaw, the boss of Centrica, has ruled himself out of the running to take the top job at BG Group, the troubled FTSE 100 energy group.

Sky News has learnt that Mr Laidlaw, whose departure from the owner of British Gas is expected to be announced within weeks, has told friends that he is not interested in the BG role.

The vacancy at the helm of BG emerged in May, when Chris Finlayson was ousted after just a year in the job, following problems with key exploration projects and a string of profit warnings.

Mr Laidlaw, who has been Centrica’s chief executive since 2006, was linked with the BG role in 2012, and was reported this weekend by one newspaper as having agreed to take the job.

However, insiders confirmed that Mr Laidlaw had had no serious discussions on either occasion with BG, which is now understood to have identified a preferred candidate to replace Mr Finlayson from outside the UK.

BG’s new chief executive could be announced at around the time of its second-quarter results at the end of next month, said one.

By coincidence, Centrica’s new boss is likely to be appointed at around the same time, with Iain Conn, a senior BP executive, involved in ongoing negotiations with the company.

Sky News revealed last monththat one of the potential obstacles to Mr Conn's appointment as Centrica's new boss is his multimillion pound shareholding in BP, a significant proportion of which has yet to pay out.

BP's latest annual report shows that Mr Conn owns approximately £3m-worth of BP shares and has about £16m-worth of additional awards which are subject to performance criteria.

Mr Conn had also been sounded out about joining BG, but is not thought to be in talks about that role.

British Gas is often confused with BG Group, although the two are now entirely separate companies after being privatised by Margaret Thatcher in 1986.

Centrica plc was created in 1997 following a demerger from British Gas plc, which was then renamed BG.

BG now has a market value of just over £43bn, and is repeatedly touted as a takeover target for the likes of Exxon-Mobil, America’s biggest energy group.

Centrica’s market value stands at £16.45bn, with its shares having fallen by more than 12% during the last year as political heat on the major domestic energy suppliers has intensified.